Diabetic nephropathy in adolescence: appearance during improved glycemic control

Two girls, aged 15 and 14 years, with poorly controlled insulin-dependent diabetes (IDD) of 9 and 7 years duration, respectively, developed overt and persistent proteinuria shortly after rapid increases in insulin therapy and improved glycemic control. Renal biopsies showed diffuse diabetic glomerulosclerosis. Both patients maintained normal or increased creatinine clearances. Direct ophthalmoscopy and fluorescein retinal angiography demonstrated nonproliferative diabetic retinopathy in the first patient, which deteriorated after 6 weeks of strict metabolic control; the second patient had normal retinas. The appearance of clinical proteinuria during this brief period of good glycemic control suggests that the latter may have unmasked a preexisting condition. Possible pathophysiologic mechanisms initiating the proteinuria in these patients are reviewed.

Proteinuria in children with insulin-dependent diabetes: relationship to duration of disease, metabolic control, and retinal changes

The relationship of early retinal changes and subclinical proteinuria to duration and metabolic regulation of insulin-dependent diabetes was studied in 67 children. Retinopathy was found in 25 patients and occurred almost exclusively (96%) in those with duration of disease longer than five years. Glomerular filtration rate was normal or increased in all patients. Urinary excretion of beta 2-microglobulin, albumin, transferrin, and IgG was significantly increased in patients, as compared with controls, whereas serum concentrations of these proteins were generally normal. The mechanisms responsible for the hyperexcretion of both large and small proteins are unclear but probably involve both glomerular and tubular dysfunction. Increased urinary protein excretion occurred independently of duration of disease. Retinopathy but not microproteinuria was more common in patients with glycosylated hemoglobin greater than 11% and in those with duration of disease longer than five years. Although a significant association was found between retinopathy and the hyperexcretion of one or more of the large molecular weight proteins, the weight of the evidence suggests that these two sequelae of diabetes differ in their pathogenesis. Long-term follow-up of these patients may provide insight as to their risk of developing more serious retinopathy or nephropathy, and whether good glycemic control may protect against these complications of insulin-dependent diabetes.

Phosphate replacement during treatment of diabetic ketosis. Effects on calcium and phosphorus homeostasis

Thirty-five patients with diabetic ketosis were given initial intravenous (IV) potassium replacement as phosphate (N = 13) or chloride (N = 13), or received no potassium replacement other than that contained in a normal diet (N = 9). All patients experienced a slight decrease in serum calcium level by 12 hours after the start of insulin therapy, but there was no statistically significant change in serum ionized calcium values. The phosphorus-supplemented group had significantly lower serum phosphorus concentrations at 24 and 36 hours when compared with patients receiving no IV hydration and excreted significantly more phosphorus during the first 12 hours of the study than either of the other two groups of patients. Our use of phosphorus supplements (4.7 to 28.5 mg/kg) did not cause abnormalities in calcium metabolism but did not prevent late hypophosphatemia.

Diurnal glucose--dependent fluctuations in glycosylated hemoglobin levels in insulin-dependent diabetes

In order to evaluate the relationship between short-term glycemic control and the stable and labile fractions of GHb, we performed hourly blood glucose samplings for 24 hr on 31 occasions in 13 children with IDDM of varying duration. GHb was measured both in hemolysates of whole blood and after 48 hr incubation at 4 degrees C in normal saline to remove the labile fraction of GHb. SI-GHb was always lower than WB-GHb (p less than 0.0001). MGB correlates closely with WB-GHb (r = 0.58, p less than 0.001) and less closely with SI-GHb (r = 0.45, p less than 0.05). The daily fluctuations in SI-GHb were always significantly less than in WB-GHb (p less than 0.005). The labile fraction correlated closely with MAGE (r = 0.62, p less than 0.0001). In one subject WB-GHb decreased by 4.4% and SI-GHb by 3.1% over a 7 wk period of good glycemic control. These results (1) confirm the presence of the stable and liable forms of GHb; (2) a closer correlation of short-term control with WB-then SI-GHb; and (3) highlight the possible relationship of the labile fraction of GHb to diabetic instability as assessed by MAGE.

Effects of enhanced conventional therapy on metabolic control in children with insulin-dependent diabetes mellitus

We implemented a three-phase, 32-wk program to improve both self-regulation of adherence behaviors and insulin delivery in children with diabetes. Twenty children, aged 8-12 yr (mean duration 3.6 yr), enrolled. Phase 1 (wk 1-12) used behavior modification to improve diet, exercise, urine testing, and insulin adjustment, targeting an increased percentage negative urines. Feedback training and parent checks were used to improve reliability; adherence was measured using Clinitest placebos. Phase 2 (wk 13-20) was a stabilization period. Phase 3 (wk 21-32) studied the effect of insulin dose adjustment, comparing once-versus twice-daily shots in 10 pairs of children matched for %GHb. GHb, fasting plasma glucose, and lipids were measured at baseline and at the end of each phase. Results revealed a significant and sustained increase in negative urine tests, but no change in % GHb or FBG. Reliability of and adherence to urine tests were 83% and 76%, respectively. During phase 3, no significant differences were noted between groups receiving once- or twice-daily insulin injections. Thus, behavior modification resulted in increased reliability and adherence to routines, associated with a reliable increase in negative urines. This did not, however, produce changes in other control measures. Furthermore, no differences between those receiving 1 or 2 daily shots were evident.

Age and sex variations in glucose tolerance and insulin responses: parallels with cardiovascular risk

The venous plasma glucose and insulin concentrations recorded during oral glucose tolerance testing of over 300 1st degree relatives (parents and siblings) of insulin dependent diabetics are presented. Men had higher glucose concentrations than women, the difference increasing with age, while insulin responses appeared greater in adolescent girls and young women than their male counterparts. The possible relationship between the different insulin responses in the two sexes and the sex difference in cardiovascular risk factors is discussed. It is suggested that the absence of a marked sex differential in heart disease mortality amongst diabetics may partly result from the loss by diabetic women of their greater insulin production relative to men in young adult life.

Factors affecting glycosylated hemoglobin values in children with insulin-dependent diabetes

In 477 children with IDD treated by conventional methods, GHb (microcolumn chromatography) and a simultaneous random blood glucose concentration were measured over an 18-month period as indicators of metabolic control (once in 61 children, twice in 99, three or more times in 317). The data were analyzed to assess the effects of patient's age, sex, disease duration, and, in a random subgroup of 273, the number of daily insulin injections and insulin dose (U/kg). The mean +/- SEM percent GHb over this period was 11.8 +/- 0.2% and blood glucose concentration 237 +/- 9 mg/dl. Only seven children (1.4%) had a normal GHb value. There was a highly significant correlation between GHb and both age and blood glucose concentration but not with disease duration greater than one year. The correlation with age was present only in the girls. In 416 children evaluated more than once, with a mean duration between initial and most recent evaluations of 11.3 months, GHb remained within +/- 1% of the initial value in 40.5%, decreased in 32.3%, and increased in 24.2%. These data indicate a closer relationship between metabolic control in children with IDD and age of the child, particularly in females, than with disease duration. In our clinic, using conventional therapeutic methods, the ability to improve control over the short term as measured by changes in percent GHb has been quite limited. This study helps to target those IDD children, especially adolescent girls, requiring a more aggressive therapeutic approach.

Electroencephalographic changes in diabetic ketosis in children with newly and previously diagnosed insulin-dependent diabetes mellitus

Abnormal electroencephalograms in patients with long-standing diabetes mellitus have been attributed to hypoglycemia. EEG changes in newly diagnosed patients or in patients during episodes of diabetic ketoacidosis have not previously been reported. We performed serial EEGs at one, 12, 24 hours and five days after initiation of treatment for DKA on 39 patients aged 11 months to 16 years with newly or previously diagnosed insulin-dependent diabetes mellitus. Twenty-seven patients were in ketoacidosis and 12 patients ketotic only. Abnormal EEGs were found in 30 patients on admission. The EEG changes at one hour, classified in order of increasing severity, correlated with the serum glucose, osmolality, bicarbonate, beta-hydroxybutyrate, and acetoacetate values, but not with pH or glycosylated hemoglobin. The rate of improvement of the EEGs was unaffected by the addition of phosphate to the intravenous fluids during therapy. EEG changes persisted in five of the seven children who had follow-up studies at two to five months, and in two of the six children one year after admission. We conclude that EEG changes are common in children with DKA or ketosis, the severity of the abnormalities being most closely associated with the degree of hyperosmolality rather than acidosis. These changes may persist in some cases, possibly accounting for the increased frequency of EEG abnormalities in diabetic children.

The effects of water deprivation and water loading during treatment with 1-deamino-8-D-arginine vasopressin in central diabetes insipidus in childhood

Nine children aged 7 2/12 to 17 9/12 years with central diabetes insipidus were subjected to water deprivation and water loading during treatment with 1-deamino-8-D-arginine vasopressin (DDVAP). Urine output remained unchanged despite the large differences in water intake. Serum osmolarity was not significantly affected by water deprivation. However, there was a marked decrease in serum osmolarity during water loading. This not accompanied by any symptoms of haemodilution. Thus patients apparently tolerate large variations in fluid intake during therapy with DDVAP.

Progressive retinopathy with improved control in diabetic dwarfism (Mauriac's syndrome)

We report four children aged 11-18 1/2 yr first seen 7-14 yr after the diagnosis of insulin-dependent diabetes. At presentation, all had marked short stature, two had hepatomegaly, and the older three had delayed adolescence. They had been severely underinsulinized. Initial funduscopy demonstrated only occasion microaneurysms in two children and a single intraretinal hemorrhage in another. The youngest was normal. Improved control required large increases in insulin dosage. Growth rate improved significantly and hepatomegaly regressed. Puberty progressed rapidly in two older patients with poor final height. Paradoxically, with improved control, retinopathy progressed rapidly with appearance of multiple microaneurysms, nerve fiber layer infarctions, intraretinal microangiopathic changes, hemorrhages, exudates, and macular edema in all the patients and severe proliferation changes in three. One child with proliferative retinopathy in both eyes developed vitreous hemorrhage and blindness in one eye. Two required panretinal photocoagulation with no further progression of their retinopathy. These rapidly progressive retinal changes remain unexplained. We advise caution when correcting metabolic derangements of diabetic patients who have been poorly controlled for a prolonged period.

Glucose polymer tolerance in premature infants

Some formulas designed for premature infants contain glucose polymer (GP) as part of their carbohydrate content. GP tolerance tests and lactose tolerance tests were performed on 11 healthy premature infants at 2 to 3 weeks of age to compare their ability to digest and absorb GP and lactose. Total plasma reducing substances (TPRS), plasma insulin (PI), and plasma glucose were measured 10 minutes before and 30, 60, and 120 minutes after the oral carbohydrate test meal. Lactose and GP stimulated a significant increase in TPRS at 30 and 60 minutes and produced similar glycemic responses. However, GP stimulated PI response whether measured as the area under the PI response curve or as the PI/TPRS ratio. It was concluded that although GP and lactose evoke similar glycemic responses, they differ in their abilities to stimulate insulin secretion. The mechanism controlling this differential insulin response is unknown.

Glycosylated haemoglobin in children with insulin-dependent diabetes mellitus

Glycosylated haemoglobin (HbA1) was measured serially by microcolumn chromatography in 38 children with newly diagnosed insulin-dependent diabetes. Initial HbA1 levels of 13.6 +/- 0.5% fell signficiantly from day 0 (prior to therapy) both to day 1 (1.6 +/- 0.2% decrease) and to day 3-5 (2.6 +/- 0.4% decrease) (P < 0.001). This drop correlated closely with changes in blood glucose (P < 0.001), less closely and inversely with plasma bicarbonate levels (P < 0.01), but not with prior duration of symptoms or changes in serum cholesterol and triglyceride concentrations. HbA1 levels reached a nadir of 8.2 +/- 0.3% 3 weeks to 6 months after diagnosis, and correlated with decreasing insulin dosage (P < 0.001). HbA1 levels rose again to 11.4 +/- 0.5% in 21 patients followed for more than 3-6 months. Our results indicate that (1) HbA1 level change rapidly during initial stabilization of insulin-dependent diabetes suggesting that glycosylation may not be entirely irreversible, and (2) HbA1 levels are consistent with clinical assessment of control during remission and postremission phases.

1-deamino-8-D-arginine vasopressin in the treatment of central diabetes insipidus in childhood

The effectiveness of therapy with carbamazepine and clofibrate (oral therapy), intramuscular pitressin-in-oil, and intranasal 1-deamino-8-D-arginine vasopressin has been compared in 15 children with partial or complete central diabetes insipidus. Mean daily urine volume without therapy was 5.4 l and dropped to 1.1 and 1.6 l/day while receiving pitressin and DDAVP, respectively. Oral agents decreased the daily urine volume to 2.2 l in patients with partial DI, with good symptomatic control except for some nocturia. These agents had no effect in patients with complete DI and did not alter pitressin requirements. Duration of pitressin action was 24 to 36 hours with a significant incidence of hyponatremia. The duration of DDAVP effect was 8 to 20 hours, varying in individual patients. Children with partial DI required smaller doses of DDAVP and the duration of action was longer than in those with complete DI. Control of serum electrolytes was excellent using two doses per day and nocturia was eliminated. All patients who had received pitressin had growth hormone antibodies, but continued to grow normally unless there was pre-existing growth hormone deficiency. These antibodies gradually disappeared after approximately one year of therapy with oral agents or DDAVP. DDAVP did not alter growth hormone, cortisol, or prolactin levels during sleep. DDAVP is the antidiuretic therapy of choice in children with either complete or partial DI; to date, no side effects have been demonstrated.

The effect of cyproheptadine and human growth hormone on adrenocortical function in children with hypopituitarism

The cortisol response to insulin hypoglycemia was determined in ten hypopituitary children treated for four months with both growth hormone and cyproheptadine, and in six other children with hypopituitarism treated for four months with hGH alone. All patients had previously normal responses to orally administered metyrapone. There was no demonstrable difference in the F responses to insulin hypoglycemia before and four months following its discontinuation in the patients receiving hGH alone. In the ten patients on combined therapy the F response to insulin hypoglycemia was normal in five and subnormal in five patients. These ten patients were retested at least two months after cessation of CPH therapy. The F response reverted to normal in four of the five patients in whom it had been subnormal. There was no significant change in the five patients with initial normal response. No patients had signs or symptoms of glucocorticoid insufficiency. In some cases, long-term administration of CPH to children with hypopituitarism is associated with decreased F response to insulin hypoglycemia; this may represent decreased adrenocortical reserve in these patients. The previously reported enhancement of growth of hypopituitary children treated with hGH and CPH may in part be a result of decreased F production.

Prolactin responses to thyrotropin-releasing hromone in protein-calorie malnutrition

Basal plasma prolactin (hPRL) concentration is low, but the response to thyrotropin-releasing hormone (TRH) is within the normal range, in children with protein-carlorie malnutrition (PCM) before treatment. Treatment results in increased basal hPRL concentration and an increased response to TRH. The above findings contrast with normal or high basal TSH and the normal or exaggerated response to TRH provocation in untreated PCM. The reason for this divergence is obscure.

The effect of alanine infusions on growth hormone, insulin, and glucose in protein-calorie malnutrition

In view of the previously reported inverse correlation between the elevated serum growth hormone (HGH) and low alanine in children with protein-calorie malnutrition (PCM), 30-min alanine infusions were performed in five children with PCM and 12-hr infusions in four children before and after therapy. These infusions did not lower basal HGH or improve its glucose suppressibility in untreated PCM, excluding a feedback relationship between HGH and alanine. There was no insulinotropic effect during 30-min infusions, but an improved insulin response to glucose after the 12-hr alanine infusion was found in three of four children before therapy. Plasma glucose rose slightly during alanine infusion in three of five children before treatment, but the magnitude of change was small and the relevance unclear.

Early insulin release and its response to potassium supplementation in protein-calorie malnutrition

Early insulin release after oral glucose is absent in protein-calorie malnutrition (PCM). There is an increase of the insulin-glucose ratio at 10 and 15 min induced by potassium supplementation compared to a similar group receiving an identical diet without supplementary potassium. This suggests that impaired insulin secretion in PMC is in part due to a potassium mediated disturbance of insulin release.

Potassium supplementation, serum immunoreactive insulin concentrations and glucose tolerance in protein-energy malnutrition

The serum immunoreactive insulin (IRI) concentrations, and glucose dissappearance rate-constants after intravenous glucose administration were measured on admission and during recovery in children suffering from protein-energy malnutrition (PEM). 2. A high potassium intake resulted in a considerable increase in the serum IRI levels early in the treatment period. There was a definite relationship between potassium depletion and many measurements of insulin secretion. 3. The results are consistent with the hypothesis that impaired insulin release in children suffering from PEM is partly the result of potassium depletion.

Circulating "big" insulin in protein-energy malnutrition

1. The ‘big’ insulin content of the serums from ten children with protein–energy malnutrition was estimated before, during and after 3–6 weeks of treatment. The values for immunoreactive insulin (IRI) after intravenous injections of glucose were almost normal, with one exception, although tolerance was impaired. In addition, total body potassium content (TBK) was measured for three of the children on each test day.

2. In nine of twenty-three estimations ‘big’ insulin content was slightly more than 20% of the total IRI. However, there was a wide fluctuation in the values and no change was noted after treatment.

3. The amount of ‘big’ insulin did not correlate with either the magnitude of insulin secretion, the insulin:glucose ratio or TBK. There was a barely significant negative correlation between ‘big’ insulin content and degree of glucose intolerance, with some individual exceptions.

Insulin secretion in protein-calorie malnutrition. I. Quantitative abnormalities and response to treatment

Immunoreactive insulin (IRI) responses to oral and/or intravenous (IV) glucose were measured in kwashiorkor and marasmus. Responses were expressed either as peak IRI levels attained or as insulin-glucose ratios. Similar measurements were made in normal controls.

After oral glucose, insulin secretion was abnormally low in every patient with kwashiorkor and in most of the marasmic cases. After IV glucose, normal insulin responses were noted more often, presumably associated with the greater glycemic stimulus. This was particularly noticeable in marasmus.

In both groups of subjects there was improvement after three to six weeks therapy, but this was much more striking after oral glucose. However, in many patients, insulin secretion remained subnormal or even deteriorated at this time, when nutritional status had greatly improved. Two to ten months later however, insulin levels were judged to be within normal limits in these cases. Children known to have suffered from kwashiorkor ten years previously likewise had normal insulin responses in 90 per cent of cases.

Augmented stimulation by glucose plus glucagon revealed some pancreatic insulin reserve in half the untreated patients studied. Yet the responses to augmented testing improved still further in three of five cases after therapy.

Insulin secretion is grossly impaired in kwashiorkor and marasmus. However, it is increased in many cases either by a greater glycemic stimulus or by adding glucagon to the glucose load. This suggests a “sluggishness” of insulin release after glucose under conventional conditions of testing in these cases. The disproportionate improvement after therapy in the insulin response to oral, as opposed to IV, glucose, may provide some evidence that an impaired gut betacytotrophic mechanism is partly responsible for the altered release mechanisms.